from scipy.spatial.distance import cdist
from scipy.optimize import linear_sum_assignment
import numpy as np 


def zeromean_normalize(vertices):
    vertices = np.array(vertices)
    vertices = vertices - vertices.mean(axis=0)
    vertices = vertices / (1e-6 + np.linalg.norm(vertices, axis=1)[:, None]) # project all verts to sphere (not what we meant)
    return vertices

def preregister_mean_std(verts_to_transform, target_verts, single_scale=True):
    mu_target = target_verts.mean(axis=0)
    mu_in = verts_to_transform.mean(axis=0)
    std_target = np.std(target_verts, axis=0)
    std_in = np.std(verts_to_transform, axis=0)
    
    if np.any(std_in == 0):
        std_in[std_in == 0] = 1
    if np.any(std_target == 0):
        std_target[std_target == 0] = 1
    if np.any(np.isnan(std_in)):
        std_in[np.isnan(std_in)] = 1
    if np.any(np.isnan(std_target)):
        std_target[np.isnan(std_target)] = 1
        
    if single_scale:
        std_target = np.linalg.norm(std_target)
        std_in = np.linalg.norm(std_in)
    
    transformed_verts = (verts_to_transform - mu_in) / std_in
    transformed_verts = transformed_verts * std_target + mu_target
    
    return transformed_verts


def compute_WED(pd_vertices, pd_edges, gt_vertices, gt_edges, cv=100.0, ce=1.0, normalized=True, prenorm=False, preregister=True, register=True, single_scale=True):
    pd_vertices = np.array(pd_vertices)
    gt_vertices = np.array(gt_vertices)
    
    # Step 0: Prenormalize / preregister
    if prenorm:
        pd_vertices = zeromean_normalize(pd_vertices)
        gt_vertices = zeromean_normalize(gt_vertices)
        
    if preregister:
        pd_vertices = preregister_mean_std(pd_vertices, gt_vertices, single_scale=single_scale)
        

    pd_edges = np.array(pd_edges)
    gt_edges = np.array(gt_edges)
    

    # Step 0.5: Register
    if register:
        # find the optimal rotation, translation, and scale
        from scipy.spatial.transform import Rotation as R
        from scipy.optimize import minimize
        
        def transform(x, pd_vertices):
            # x is a 7-element vector, first 3 elements are the rotation vector, next 3 elements are the translation vector, finally scale
            rotation = R.from_rotvec(x[:3])
            translation = x[3:6]
            scale = x[6]
            return scale * rotation.apply(pd_vertices) + translation
        
        def cost_function(x, pd_vertices, gt_vertices):
            pd_vertices_transformed = transform(x, pd_vertices)
            distances = cdist(pd_vertices_transformed, gt_vertices, metric='euclidean')
            row_ind, col_ind = linear_sum_assignment(distances)
            translation_costs = np.sum(distances[row_ind, col_ind])
            
            return translation_costs
        
        x0 = np.array([0, 0, 0, 0, 0, 0, 1])
        # minimize subject to scale > 1e-6
        # res = minimize(cost_function, x0, args=(pd_vertices, gt_vertices), constraints={'type': 'ineq', 'fun': lambda x: x[6] - 1e-6})
        res = minimize(cost_function, x0, args=(pd_vertices, gt_vertices), bounds=[(-np.pi, np.pi), (-np.pi, np.pi), (-np.pi, np.pi), (-500, 500), (-500, 500), (-500, 500), (0.1, 3)])
        # print("scale:", res.x)

        pd_vertices = transform(res.x, pd_vertices) 
        
    
    # Step 1: Bipartite Matching
    distances = cdist(pd_vertices, gt_vertices, metric='euclidean')
    row_ind, col_ind = linear_sum_assignment(distances)
        
    
    # Step 2: Vertex Translation
    translation_costs = np.sum(distances[row_ind, col_ind])
    
    # Additional: Vertex Deletion
    unmatched_pd_indices = set(range(len(pd_vertices))) - set(row_ind)
    deletion_costs = cv * len(unmatched_pd_indices)  
    
    # Step 3: Vertex Insertion
    unmatched_gt_indices = set(range(len(gt_vertices))) - set(col_ind)
    insertion_costs = cv * len(unmatched_gt_indices)  
    
    # Step 4: Edge Deletion and Insertion
    updated_pd_edges = [(col_ind[np.where(row_ind == edge[0])[0][0]], col_ind[np.where(row_ind == edge[1])[0][0]]) for edge in pd_edges if edge[0] in row_ind and edge[1] in row_ind]
    pd_edges_set = set(map(tuple, [set(edge) for edge in updated_pd_edges]))
    gt_edges_set = set(map(tuple, [set(edge) for edge in gt_edges]))

    
    # Delete edges not in ground truth
    edges_to_delete = pd_edges_set - gt_edges_set
    
    #deletion_edge_costs = ce * sum(np.linalg.norm(pd_vertices[edge[0]] - pd_vertices[edge[1]]) for edge in edges_to_delete)
    vert_tf = [np.where(col_ind == v)[0][0] if v in col_ind else 0 for v in range(len(gt_vertices))]
    deletion_edge_costs = ce * sum(np.linalg.norm(pd_vertices[vert_tf[edge[0]]] - pd_vertices[vert_tf[edge[1]]]) for edge in edges_to_delete)

    
    # Insert missing edges from ground truth
    edges_to_insert = gt_edges_set - pd_edges_set
    insertion_edge_costs = ce * sum(np.linalg.norm(gt_vertices[edge[0]] - gt_vertices[edge[1]]) for edge in edges_to_insert) 
    
    # Step 5: Calculation of WED
    WED = translation_costs + deletion_costs + insertion_costs + deletion_edge_costs + insertion_edge_costs
    # print("translation_costs, deletion_costs, insertion_costs, deletion_edge_costs, insertion_edge_costs")
    # print(translation_costs, deletion_costs, insertion_costs, deletion_edge_costs, insertion_edge_costs)
    
    if normalized:
        total_length_of_gt_edges = np.linalg.norm((gt_vertices[gt_edges[:, 0]] - gt_vertices[gt_edges[:, 1]]), axis=1).sum()
        WED = WED / total_length_of_gt_edges
        
    # print ("Total length", total_length_of_gt_edges)
    return WED